When is it time to buy new runners?

Of all the questions surrounding the relatively simple sport of running, one of the curliest has to be how to know when it’s time for new shoes.

You don’t want to leave it too long and risk injury. But you also don’t want to spend money unnecessarily. Your running buddy changes his shoes religiously every 12 weeks. Another swears by the 500km rule. Some people have several pairs on rotation.

“There’s no hard and fast rule, because a lot of factors need to be considered,” says Sydney physiotherapist and running technique expert Mark Green. Green is also one of the top off-road ultramarathoners in NSW, and a former elite ironman triathlete.

Age vs distance

Time and distance rules around shoe longevity are too arbitrary for Green’s liking. He says your running technique is the better indicator.

“If you learn to run well you will rely more on your body and less on your shoes,” he says. “I don’t mean learning to run fast, I mean technically well. When this happens, my experience is that people don’t wear their shoes out so quickly and they last longer.”

“You’ll know the time was right to change if your body bounces back quicker.”

Mark Green

Conversely, the worse your running technique, the more important shoes are. And the more often you’ll need to replace them.

Other factors such as body weight will make a difference, as will how densely cushioned, or how minimalist the shoes are.

Time to trade up

Green’s general advice on picking a worn-out running shoe is to start by looking at the soles.

“Overstriders, for example, might find the signs at the outside corner of the heel. If the hard rubber sole is starting to wear down to a layer where it’s a different colour, you’re not getting the cushioning or support you need any more from your shoe,” he says.

“For people who have been taught not to heel-strike, the front outside can wear out first, the part of the shoe known as the lateral forefoot.

“Some people wear out the uppers; if the shoe has got tears along the outside of the forefoot or their big toe is coming through, then it’s time to change.

“If your knee starts niggling or some other issues start occurring and you haven’t done anything differently, it might be a sign to re-invest.”

Finally, Green says that if you start feeling like a pair of shoes is getting tired because you’re not recovering quite so quickly from a run, replace them and run in both to compare the difference. “Sure, the new ones will feel more springy, but you’ll know the time was right to change if your body bounces back quicker,” he says.

The danger of worn shoes

The risk of wearing your runners past their use-by date is injury. Green says a worn-out forefoot, for example, can lead to foot pain, shin pain and issues such as plantar fasciitis.

“Your foot will roll in [pronate] further and faster in a worn-out pair of shoes, and this increased rocking motion will put more stress on the foot and shin”.

Two of the biggest contributing factors to running injuries are doing too much too soon, and poor technique.

Strategy for success

Depending on the runner, their training needs and previous history, one option Green suggests is to buy three pairs of running shoes, each slightly different in pitch and cushioning.

Of course, the different features of each pair still need to match the activities, training requirements and biomechanics of the runner. Getting this wrong can lead to changes in technique, which could induce injury if the body overcompensates.

“Choose different brands if you want to, obviously make sure they’re comfortable, and wear them all regularly,” says Green. “The idea is to put your body under a different load each time you run, so the stress on your body is slightly different.

“Most injuries are caused by repetition, so wearing different shoes helps to mitigate this risk.”